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How to drain Calorifier


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Help please! 
 

fitting new calorifier tank today and just gone to drain the system by shutting off the water feed from the holding tank to the pump and opening all taps but the pump runs and water doesn’t come out! 
 

i haven’t seen a shut off valve anywhere on the cold feed line into the calorifier so I’m struggling to understand how I can drain the tank in order to disconnect and remove it! 
 

any suggestions? 
 

thanks in advance :) 

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9 minutes ago, Katie said:

...shutting off the water feed from the holding tank to the pump and opening all taps but the pump runs and water doesn’t come out! 

...

... which is all good so far, and hopefully shows the valve from the holding tank to the pump is successfully keeping water in the water tank. Best to deny the pump its electricity so that it doesn't try to pump water when there is none-to-pump and burning out.

 

Next job is to find a valve low-down-somewhere to drain the engine-water and, separately, to drain the hot-water-system before undoing all those calorifier-connecting pipes. Can be fiddly ... someone will be along in a mo with some photos ... ?? 🙂

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There is no water coming because  air cannot get in to replace it.

 

Turn OFF  the valve at the outlet of the cold water tank.

Disconnect the pipe from the pump inlet.

Open all taps. 

Turn the pump ON.

When water stops coming, switch pump OFF.

 Disconnect engine and or boiler connections to the calorifier, catching the water that comes out.

 Disconnect tap water connections to calorifier.  Water will probably come out and need catching.

Remove calorifier.

 

Some pictures of the pump and the calorifier would help.

 

N

 

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2 hours ago, Katie said:

 shutting off the water feed from the holding tank to the pump and opening all taps but the pump runs and water doesn’t come out! 

As said above, the pump is starved. Most pumps will pump air, so

1. Turn the pump off.

2. Turn off the water feed from the holding tank at the stop cock.

3. Open all the taps, hot and cold.

4. Undo the pipe somewhere between the stop cock and the pump. Have a rag ready as a little water will leak.

5. Turn the pump on, it should now suck in air and blow this through the pipes.

 

The problem can be emptying the calorifier as the hot water outlet is at the top. On my horizontal one, when the pump is running on air as per step 5,

 

6. Close all the taps and the calorifier pressures up.

7. Release the pressure relief valve (PRV) by turning the red knob, the air pressure in the top of the calorifier will blow the water out of the bottom.

8. Close the PRV and repeat step 7 until air blows out.

9. Turn off the pump, reconnect the water feed pipe and open the taps.

10. Disconnect the heating water coils and 230V immersion cable as required.

Edited by PeterF
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You will end up with puddles whatever you do but basically as BEngo say's, stop new water coming in, turn off pump, drain water from the lowest possible point, and remove the thing, there is not much water / antifreeze in the engine circuit (usually) but its a soggy exercise whatever you do and if you can avoid it then its best to leave it well alone. 

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Thanks just tried shutting off valve from water tank and disconnecting the inlet to the water pump. Opened all taps and didn’t work. Just a trickle of water and then basically stopped. 
 

at this point I think it’s just easier to drain the whole system including water tank. 
 

 

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2 minutes ago, Katie said:

Thanks just tried shutting off valve from water tank and disconnecting the inlet to the water pump. Opened all taps and didn’t work. Just a trickle of water and then basically stopped. 
 

at this point I think it’s just easier to drain the whole system including water tank. 
 

 

There is absolutely no need to drain the water tank.

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You will I think need a drain point at the lowest point in the system. There's no other way of getting water out of the tank  - you can't blow it out as the outlet is at the top.  I have one on the cold feed near where it goes into the tank (top right in this picture, the one just below is connected to the outlet side of the tank). This is connected to a pump to get the water out.

bilgepump.jpg.2073bd2502e7e5a4e8cdb8af9eb632bc.jpg

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3 minutes ago, Tracy D'arth said:

There is absolutely no need to drain the water tank.

Haha ok thanks for this

 

as I said I tried the suggestions above by closing stopcock and disconnecting the feed pipe between stopcock and pump. Ran pump with taps open and didn’t work. 

2 minutes ago, Scholar Gypsy said:

You will I think need a drain point at the lowest point in the system. There's no other way of getting water out of the tank  - you can't blow it out as the outlet is at the top.  I have one on the cold feed near where it goes into the tank (top right in this picture, the one just below is connected to the outlet side of the tank). This is connected to a pump to get the water out.

bilgepump.jpg.2073bd2502e7e5a4e8cdb8af9eb632bc.jpg

Thanks doesn’t look like I have any other shut off valves after the stopcock other than to the taps. Something we will hopefully sort when plumbing in new tank! 

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3 minutes ago, Katie said:

Haha ok thanks for this

 

as I said I tried the suggestions above by closing stopcock and disconnecting the feed pipe between stopcock and pump. Ran pump with taps open and didn’t work. 

Thanks doesn’t look like I have any other shut off valves after the stopcock other than to the taps. Something we will hopefully sort when plumbing in new tank! 

Yes. I think I have 13 isolator valves in my system, which is perhaps a bit OTT. And the pump can also be used to pump out the cabin bilges (not needed to do that for years!).

I should have said that to drain the calorifier I have all the hot water taps open, to let air into the calorifier.  Here's a sketch that you might find helpful. I have both hot and warm water systems, for galley and bathroom respectivelyplumbing.jpg.6ee6c797684355ad91774c34e06c7065.jpg

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1 hour ago, Katie said:

i haven’t seen a shut off valve anywhere on the cold feed line into the calorifier so I’m struggling to understand how I can drain the tank in order to disconnect and remove it! 

 

As Tracey says, there is no need to drain the water tank. There should be an isolator valve on the outlet from it that you can turn OFF. 

 

Once the water supply to the calorifier has been so isolated, the calorifier can only be drained by opening up a pipe connection at the base of it, e.g. the inlet supply from the pump. The installers might have had the foresight to fit a drain cock but knowing boat fitters, they probably didn't so you'll need to disconnect a pipe. And devise a way to be ready to catch all the water that will pour out.

 

The really bad news is the water supply inlet might have a non-return valve in it which prevents you doing it as described above. If you have, then you'll need to disconnect the outlet from the calorifier and dip a hose into it, and syphon it out or use a separate pump to suck it out.

 

As others keep asking, post some photos please for more specific help.

 

 

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2 minutes ago, Scholar Gypsy said:

Yes. I think I have 13 isolator valves in my system, which is perhaps a bit OTT. And the pump can also be used to pump out the cabin bilges (not needed to do that for years!).

I should have said that to drain the calorifier I have all the hot water taps open, to let air into the calorifier.  Here's a sketch that you might find helpful. I have both hot and warm water systems, for galley and bathroom respectivelyplumbing.jpg.6ee6c797684355ad91774c34e06c7065.jpg

Thanks but as I can run the taps without the stopcock open it seems, the calorifier will just keep filling back up surely. 
 

that’s a good diagram thanks

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4 minutes ago, Katie said:

Thanks but as I can run the taps without the stopcock open it seems, the calorifier will just keep filling back up surely. 
 

that’s a good diagram thanks

I'm getting confused. If the main water tank isolator is closed then where can the water come from?  Some photos of your calorifier would be really helpful.

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15 minutes ago, Scholar Gypsy said:

I'm getting confused. If the main water tank isolator is closed then where can the water come from?  Some photos of your calorifier would be really helpful.

 

It will be coming from the expansion vessel, and will stop once the contents of it have been expelled. 

 

Some photos are needed. DId anyone already mention this?

 

:giggles:

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Where are you moored? Is there a knowledgeable boater near you?  Draining water is not rocket science, its just gravity and letting air into the pipes to avoid sucking a vacuum.

If you have a wet vac, that is the easy way to get the water off the floor as fast as it runs out.

Look around the calorifier for a drain tap or a pipe disappearing into the bilge.  Get your phone to take a pix.

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I am rather confused as to what the OP has done but it seem to me it is normal have water trapped in the calorifier when you try to drain it unless you let air into it. With the drain point open or calorifier inlet connection disconnecter try twisting the PRV to a position between two clicks. That will let air in. It will be very wet unless you can get a hose onto the calorifier plus a drill pump or something simmilar.

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I drain my horizontal calorifier in the following order:- 

Turn the tank tap off, 

run pump with hot and cold taps open till they run dry

Turn off water pump at distribution/fuse board

Attach bicycle track air pump to water pipe exiting pump using homemade adapter

Pump air into calorifier (past non return valve) pressurizing it to expel water  via open taps. If your prv is plumbed outside you can also put the prv onto it's cam to pump straight overboard.

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Hi all appreciate the replies. We cracked on and got the tank out with water in it. Wasn’t as big a puddle as we expected. 
 

New tank fitted and system filled and seemingly working ok…
 

issue I have now is water pump running too far too long after running hot tap then a slight stutter as it the pump finally shits off. Pressure drop in my water pump from disconnecting it maybe? I have an accumulator tank connected directly after the pump. 
 

 

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8 hours ago, Katie said:

Hi all appreciate the replies. We cracked on and got the tank out with water in it. Wasn’t as big a puddle as we expected. 
 

New tank fitted and system filled and seemingly working ok…
 

issue I have now is water pump running too far too long after running hot tap then a slight stutter as it the pump finally shits off. Pressure drop in my water pump from disconnecting it maybe? I have an accumulator tank connected directly after the pump. 
 

 

 

You may well have air trapped in the calorifier. Especially if it is a horizontal one and the outlet connection is not right at the top. That would make it act like a giant accumulator. If it is horizontal make sure the outlet is right at the highest point and then see how it goes for a week or so because it may well clear any air.

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Thanks both. I’ll check pressure of the accumulator and expansion tank too as think most likely this. And yes we have fitted with outlet at top but could still be some air in it maybe. 
 

good news is it’s stopped burping overnight so no more leaks! :) 
 

that’s the first big DIY job done on my boat since I had it so really appreciate everyone’s input!

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Next time, think about taking the hot outlet off and stick a hose on a pump down into the bottom of the tank. Or, connect an air pump (big bicycle pump) to a hot tap and drive the water out of a cold tap (that won't get it all out but should empty most of it).

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12 minutes ago, Onewheeler said:

Next time, think about taking the hot outlet off and stick a hose on a pump down into the bottom of the tank. Or, connect an air pump (big bicycle pump) to a hot tap and drive the water out of a cold tap (that won't get it all out but should empty most of it).

 

Next time?

 

I'm still curious about why this one needed to be changed in the first place! 

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1 hour ago, Onewheeler said:

 Or, connect an air pump (big bicycle pump) to a hot tap and drive the water out of a cold tap (that won't get it all out but should empty most of it).

That won't work if there is a non return valve fitted to the calorifier inlet.

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